9-(2-Deoxy-2-fluoro-β-D-arabinofuranosyl)adenine, with CAS number 20227-41-2, is a fluorinated nucleoside analogue. Its structure features an adenine base linked to a modified sugar moiety (2'-deoxy-2'-fluoro-β-D-arabinofuranosyl), which is a key characteristic of antiviral prodrugs. This compound is a crucial intermediate in the synthesis of the antiviral drug **Fludarabine Phosphate**. Fludarabine is a purine analogue antimetabolite used primarily in the treatment of hematological malignancies, particularly B-cell chronic lymphocytic leukemia (CLL). The fluorinated arabinose sugar in its structure enhances its metabolic stability and cellular uptake, leading to inhibition of DNA synthesis and induction of apoptosis in rapidly dividing cells. As a high-purity synthetic intermediate, it is essential for the pharmaceutical manufacturing process of Fludarabine. Its classification falls under active pharmaceutical ingredient (API) intermediates and specialized nucleoside building blocks for life science research and drug development.